When an efferent lymph vessel leaves a lymph node, it may carry lymph to another lymph node by becoming its afferent lymph vessel or unite with other efferent vessels to become a lymph trunk. The lymph trunks drain into the lymph ducts, which in turn return lymph to the blood by emptying into the respective subclavian veins.

There are four pairs and an unpaired lymph trunks:

• Jugular lymph trunks
• Subclavian lymph trunks
• Bronchomediastinal lymph trunks
• Lumbar lymph trunks
• Intestinal lymph trunk—unpaired